oa Origin, Depositional Environment and Maturity of Crude Oils from the “KND” Oil Field (Se Pannonian Basin, Serbia)

The most important oil fields in Serbia are located in the northern part of the country and belong to the southeastern part of the Pannonian Basin. A third of the total crude oil production in Serbia is produced in the Velebit oil field. The second most prolific oil field is “KND” yielding about 17% of the total crude oil production. Despite its importance, only few samples were investigated to a limited extent. Therefore, oils from the “KND” oil field (near the Romanian border) were investigated to establish their origin, depositional environment, thermal maturity and age, using distributions of biomarkers and aromatic hydrocarbons, as well as results from Fourier transform infrared spectroscopy and bulk carbon isotopy. The “KND” oils have different properties in terms of biodegradation, from non-biodegraded to the 4th stage of biodegradation. However, regardless of the degree of biodegradation, oils belong to the same genetic type. The precursor organic matter originates from mixed marine/terrestrial sources, and was deposited under transitional redox conditions. The oils were generated from source rocks at the maturity corresponding to the vitrinite reflectance of 0.84–0.97%. The oils were probably derived from marine shale of Miocene age within the local depression of Srpska Crnja.